Too Much Water in the ICW
By Tom Neale, 12/13/2007
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Range Marker partially obscured
The criks are indeed risen. It’s not like a flood from rains. It’s because of two things: One is a full moon—it’s been full enough to howl at for several nights now. The other is days of onshore nor’easterly wind, sometimes small gales, sometimes full gales, but always wind. It’s a form of the wind tides I wrote about here a few weeks ago. But the moon makes the high tides higher anyway, causing all sorts of troubles, then the winds pile it on. They push the ocean up into the marsh and rivers and creeks and it keeps a lot of it from flowing back out at the appointed times of ebb.
Full Moon, early morn and high waters
So we’re seeing green square and red triangular aids to navigation that have the waves lapping at the bottom of their boards. Some we’re probably not seeing at all. We’re seeing range markers with the water covering part of the lower side of the front ranges. (Front ICW ranges are the short ones.) And we passed under a high rise bridge that today, at least, isn’t rising quite as high. It’s supposed to have a 65 foot vertical clearance but the tide board on its fenders shower there was only 63 feet of vertical clearance. That’s enough to take a sail boat mast down, not to mention VHF antennae, wind vanes, and all those other fancy gadgets we like to stick up on the tops of the mast.
But there’s more to it than just knocking your mast down. Part of the problem is that you can’t see the shore line. Where the charts say the shore is over there and where you’re used to seeing it to follow the channels in the passages, it’s now covered with water. All the marshes and low banks are no more. It’s just a broad sea all around. Sure, there are the stubs of aids to navigation sticking out of the water, but we’ve seen them so low that you can hardly tell what they are until its too late. All this makes it really easy to get lost or at least confused for a few minutes, and a few minutes is more than enough time to get into trouble and to stick’er in the mud.
Sticking’er in the mud is a favorite pursuit of we ICW travelers. Congress has made it a lot easier in recent years by failing to pass budgets that allow for maintenance dredging. (Actually, I always found sticking’er in the mud pretty easy without the assistance of congress.) But congress is also putting people out of work, hurting the economy of many maritime communities, and hurting many boating businesses. About the only things it isn’t hurting are the people who like to yell on the radio and on the web sites that they just went aground. Heck, I would never say that about myself on the internet or radio. I figure everybody knows I go aground anyway.
But today we have a different set of issues. Today, all those spots where everybody complains about sticking’er in the mud are not there. Well, they’re there, but they’re so far down you’d never know it. Everybody is cruising along with a smile on their face (except the ones with tall masts). But little do they know that this is a day in which going aground is far worse of a problem than just any old day of going aground. If you stick’er in the mud today, you’ve done a real job of getting into trouble.
High tide and Low Bridges
Much of the east coast from the Carolinas down to north Florida enjoys large commercial shrimping fleets. It seems that every year or so, we notice a large shrimp boat about a half mile up in the marsh from the creek shore, sitting high and dry like Proud Mary herself. It’s because, I’ve been told, that the shrimpers are sometimes so glad to be returning home with a hold full of critters that they occasionally have a tendency to take a short cut when they see nothing but water where the marsh used to be. (This phenomenon has nothing to do, I’m sure, with the totally false rumor that they sometimes have a drink to celebrate getting back—a bit before they’re actually back.) And when the shrimpers take these short cuts, it usually requires another abnormally high tide to float the boats back off. This may be next month or it may be next year if the high waters were caused by a combination of both wind and moon.
This can be just as true of pleasure boats. Running aground on a day like today can cause your boat to become a semi-permanent fixture up there in the marsh. So instead of relaxing and enjoying all the high water, we knowledgeable cruisers (knowledgeable of how many times we’ve already gone aground) are biting our fingernails and trying to navigate even more carefully than ever.
Some people use this type of phenomena to great advantage. Years ago we knew a guy in the Bahamas who had a very deep draft boat which he loved. He also loved hanging out on the hook in a large basin in an island. But some of the locals frowned on cruisers hanging out in their basin. You could only get to the basin from the sea through a shallow inlet. Our friend would simply wait for a moon tide with wind and go in. Then he was “trapped.” He couldn’t get out for at least another month, but he didn’t mind at all.
High Tide and Low Markers
In high water conditions we don’t feel safe just because the depth finder says there’s plenty of water under the keel. We only feel safe (relatively so) if the depth finder says there’s the amount of water under the keel that should be there at low water PLUS the amount of extra depth caused by the high water conditions. Chart depths are for mean low water—not for high water. For example, if the depth finder indicates you’re in 18 feet of water and the water level is 8 feet above mean low, but the chart shows you that the mean low is 15 feet, you’re in the wrong place or the chart is wrong (often the case these days). If you’re in the wrong place, even though you have plenty of water under your keel at the moment, you might find yourself plowing into a bank in a few hundred yards.
But it’s not a big deal. Tomorrow the moon starts getting smaller and the winds come from the southwest. Water will be flooding out the inlets on ebb tide in trillions of gallons. Soon the low tides will be extra low. And I can relax more as I wander down the coast. Going aground will be easier—but so will getting off.
Copyright 2004-2008 Tom Neale